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A research program to compare the ultimate axial capacity of vibratory and impact driven H-piles in sand was conducted at a San Francisco, CA, site. The effects of time-lapse after driving was also studied. The piles were instrumented so that both pile tip loads and load transfer along the pile could be determined. This report is an analysis of the pile load tests comparing impact and vibratory driven piles. The site is characterized, the load tests are described, the load tests results are analyzed and discussed, and recommendations and conclusions are made. Keywords: Axial loading, H-piles, Impact hammers, Vibratory hammers.

DTFH61-82-C-0038, In order to gain a better understanding of the behavior of piles in snad, an extensive search of the literature has been performed to collect data on instrumental piles driven in sand and tested under vertical loads. The load transfer characteristics of the piles were then analyzed without considering residual stresses. Wherever the data allowed it, the load transfer analysis was repeated after considering residual driving stresses. The results of this method as well as conventional and new in situ tests methods were then compared to actual load test results. Areas of critical need for further research are pointed out and recommendations are made for their implementation.

DTHF61-86-P-00736, This technical sharing report presents the summary of a pile group prediction symposium held on June 17 and 18, 1986 at the University of Maryland campus. Eleven foundation experts representing consulting firms, universities, and Federal and State transportation agencies presented their predictions on the results of single and pile group tests in sands/that were conducted on a site at the Hunter's Point Naval Base, San Francisco, California. The principal objective of the symposium was to evaluate current pile group foundations in sands. Complete reports on pile groups prediction symposium consists of the following: Vol. No. FHWA No, Short Title 1 TS-87-221 Sandy Soil; 2 TS-87-222 Clay Soil; 3 TS-87-223 Appendix A (predictor's reports on sand); 4 TS-87 -224 Appendix B (predictor's reports on clay)

DTHF61-86-P-00736, This technical sharing report presents the summary of a pile group prediction symposium held on June 17 and 18, 198 6 at the University of Maryland campus. Eleven foundation experts representing consulting firms, universities, and Federal and State transportation agencies presented their predictions on the results of single and pile group tests in sands,that were conducted on a site at the Hunter's Point Naval Base, San Francisco, California. The principal objective of the symposium was to evaluate current pile group foundations in sands.

The project focused on two main objectives: • Determining if a filter is necessary between the riprap layer and the underlying soil and then recommending design and installation guidelines for riprap filters (granular and geosynthetic). • Examining issues related to placing riprap on an abutment or riverbank slope and the associated stability of the slope and riprap. Researchers first conducted an extensive literature review. Next, a survey was sent to all state departments of transportation, contractors, and associated entities to establish the current state of the practice. The researchers then performed laboratory testing. They finally collected riprap failure case histories and analyzed them to reach recommendations

0-6935, Existing guidelines for maximum allowable scour are applicable only to piers since they are based on the stability criteria of the bridge foundations. An additional criterion must be considered when limiting scour at abutments where scour may also affect the stability of the approach embankment. Scour at spill-through abutments can cause slope stability failure of the embankment before reaching the depth endangering the foundations. This project proposed practical guidelines for determining the maximum allowable scour depth at or near spill-through abutments. This research primarily observed geotechnical failures of abutment embankments at multiple bridge sites in Texas.

0-6784, Soil nailing is a convenient and economic, stabilization method for the reinforcement of existing, excavations by installing threaded steel bars into cuts, or slopes as wall construction progresses from top, down (Figure 1). An aspect of particular concern in, the soil nail wall guideline is the creep behavior of, this type of system in high-plasticity (HP) clays (i.e., those soils with a plasticity index greater than 20)., However, soil nail walls have been constructed with, success in HP soils (particularly in Texas), and no, issues associated with creep behavior have been, observed so far, including walls that were built more, than 20 years ago. The main motivation of this, research project is to gain a better understanding of, the behavior of soil nail walls in HP clays and to, suggest possible modification to the current, guideline., In order to assess the effect of creep behavior in HP, clays, the following tasks were conducted, 1. Pullout tests on eight existing anchors installed in, 1991 at the clay site at the National Geotechnical, Experimentation Site at Texas A&M University, (NGES-TAMU) were performed to explore any, effect on the bond strength related to long-term, installation (i.e., soil ageing)., 2. Pullout tests on 16 new vertical soil nails, installed at the NGES-TAMU clay site were, carried out following different protocols to learn, about the effect of stress level on creep behavior., 3. Pullout tests on six new sacrificial nails installed, at different heights in a new soil nail wall at, Beaumont were carried out to learn about the, nail creep behavior under actual conditions., 4. The actual soil nail wall was monitored at, Beaumont (453 ft. long and 25 ft. high) for, 13 months to learn about the service load in nails, and different wall movements in time., 5. Laboratory tests (e.g., triaxial creep and, oedometer tests) were performed on samples, gathered from the two sites investigated in this, project (i.e., NGES-TAMU and Beaumont)., 6. Numerical simulations were conducted using, FLAC-3D. All components of the soil nail wall, were simulated. The simulations were first, calibrated against the pull-out tests and lab data., Then the Beaumont soil nail wall was modeled, and a parametric study was performed.

TTI: 0-6715, Drilled shafts are being constructed within the reinforced zone of mechanically stabilized earth (MSE) walls especially in the case of overpass bridges where the drilled shafts carry the bridge deck or traffic signs. The interaction between the drilled shaft and the MSE wall is not well known and not typically incorporated into the design. As part of the research project, a full-scale test was conducted in 2012 at Texas A&M University., The test was performed on an MSE wall where the backfill material was clean sand and the soil reinforcement was made of metal strips. Also two real projects were instrumented during construction, and data were gathered for one year. A numerical model was used and calibrated against the results of the three full-scale cases. Then a sensitivity analysis was performed and 64 numerical cases were modeled to understand the effect of different parameters on the interaction between the MSE wall and the drilled shaft. The data from the simulations, the full-scale test results, and the monitoring of the real site were processed, and a modification of the current guidelines was proposed for the case where there is a drilled shaft subjected to a horizontal load in the reinforced zone of the MSE wall. A design chart is presented to take into account the additional pressure on the wall created by the drilled shaft.

Drilled shafts are being constructed within the reinforced zone of mechanically stabilized earth (MSE) walls (Figure 1). The drilled shafts may be subjected to horizontal loads and push against the front of the wall. Distress of MSE wall panels has been noted in some cases, and there is a need to develop guidelines to include the drilled shaft load within the MSE wall design.

Project 0-6604, Unknown foundations affect about 9,000 bridges in Texas. For bridges over rivers, this creates a problem, regarding scour decisions as the calculated scour depth cannot be compared to the foundation depth, and a, very conservative costly approach must be taken. The objective was to develop a global approach, which, will reduce significantly the level of uncertainty associated with unknown foundations. This approach was, developed in two parts: a data mining and inference approach where no testing at the site was necessary, and, a testing approach where new tests for unknown foundations were used. The data mining and inference task, made use of existing data such as soil type, known foundations on neighboring bridges, design practice, and, the age of the bridge to infer the type and length of unknown foundation elements. The testing task consisted, of developing two geophysical techniques, resistivity and induced polarization imaging, to obtain a picture of, the soil and foundation below the surface level or river bottom. The outcome was a global framework in, which one of the approaches or any combination thereof, as well as the most useful current techniques, (nondestructive testing methods if necessary), can be used to decrease dramatically the uncertainty associated, with the unknown foundation. The inference process was trained by using bridges where the foundation was, known and verified by comparison against case histories. The two testing techniques mentioned above were, tested at the National Geotechnical Testing Site on Texas A&M's Riverside campus and then against, full-scale bridges selected in cooperation with TxDOT.